At certain times, commercial animals, such as, for example, livestock and/or domestic pets may not be able to readily meet their nutritional requirements by normal means. For example, during periods of stress the animal's digestive efficiency and/or amount of feed consumed may be reduced. As a result, overall productivity may be reduced. The reduced productivity may also have consequences on the economics of a livestock production facility and/or the overall health of the animals.
Stress to an animal can result from a variety of factors, such as, for example, changes in environment, feed, or health. For example, during pregnancy and/or the period around parturition (up to 4 weeks prior to and 8 weeks post birth), the animal undergoes a rapid and extensive adjustment in metabolic and productive demands. Other periods of stress may include times of nutrient shortfall, illness, changes in social environment, and changes in environmental conditions, for example, changes in location, transportation, increases or decreases in temperature or other changes in weather conditions (such as, for example, increased humidity or storms), and changes in feed composition or feeding patterns. During these periods of stress, the animal may not consume sufficient nutrients for an energy balance. As used herein, the term “energy balance” includes a balance where the energy associated with the animal's dietary consumption is substantially equal to the energy expenditures by the animal. As used herein, the term “energy imbalance” includes where the energy associated with the animal's dietary consumption is less than the energy expenditures by the animal.
Animals, including ruminants, rely heavily on sugar carbohydrates predominantly for the function of cellular metabolism, including, for example in the liver and the mammary glands. However, in ruminants fed carbohydrates, such as glucose, the carbohydrates are fermented by the rumen microflora, and no considerable amount of the simple sugars pass through the rumen into the post-rumen portion of the digestive tract intact. As a result, the ruminants must produce intact glucose in the liver to support the carbohydrate needs of the animal. Under normal conditions, the liver may provide the required amounts of carbohydrates. However, in times of stress an energy imbalance may develop.
For example, bovines, such as, dairy cattle and beef cattle, may have a negative energy balance in the period surrounding calving. Other livestock, such as, porcines, equines, ovines, caprines, and others may also suffer from negative energy balances during pregnancy and the period immediately afterwards (i.e., during lactation). As used herein, the term “negative energy balance” is synonomous with “energy imbalance” and refers to when the energy intake associated with the animal's dietary consumption is less than the amount of energy expended by the animal. This energy imbalance may begin during times of stress, such as, immediately prior to parturition and may persist through the first several weeks of lactation. During this period, dietary intake may be insufficient to supply the energy needed to meet the nutritional requirements associated with the rapidly rising production of milk. Large metabolic adjustments are required to support birth, recovery, and milk production, and productive and health concerns may arise in response to the metabolic demands.
Lack of sufficient nutrition prior to and after birth may result in extensive mobilization of body reserves of the mother, such as release or production of free fatty acids, to continue support for milk production. Fatty acid mobilization may exceed the capacity of the liver to process the fatty acids into energy sources, such as acetyl CoA and ketones, which may result in fat accumulation in the liver. This fat accumulation may further inhibit glucose production in the liver, further exacerbating the underlying energy deficit. This compounding problem may limit milk production and/or may impact health via a variety of metabolic disorders.
One approach to alleviate some of the immediate energy demands and metabolic derangement for animals near the time of birthing, such as, for example, cattle prior to, during, and after calving, may involve feed additives such as propylene glycol and calcium propionate being dosed or fed in the diet. However, these compounds may have management limitations from a producer's perspective. In addition, to be metabolically effective in bovines and/or other ruminants, substantial amounts of the glucose precursors must make it to the small intestine, for example, by making it through the rumen substantially intact. However, because intake is limited and the rumen fermentation process may still be adjusting to the increased energy density and demands, it may not be feasible to merely increase the amount of energy dense feed supplied to the animal. Starch or fat, as energy sources, used in excess within the diet may present problems for the rumen fermentation and place the animal at risk as well.
Further, in ruminants the amount of these glucose precursors that escapes fermentation in the rumen is variable and may potentially be affected by microbial adaptation. This may require that greater amounts of these compounds be fed to the animal in order to elicit a comparable response.
Sugar alcohols have been used in ruminant feed to enhance milk production. In U.S. Pat. No. 4,127,676 to Merensalmi, a fodder additive for ruminants comprising at least one sugar alcohol having five or six hydroxyl groups is disclosed. In U.S. Pat. No. 6,440,447 to Luhman, a method for enhancing milk production by a ruminant comprising feeding the ruminant a feed that contains sorbitol is disclosed. Monomeric glycerol has also been utilized as a glucose precursor both to affect metabolism (R. B. Johnson, “The Treatment of Ketosis with Glycerol and Propylene Glycol,” in The Cornell Veterinarian, Volume XLIV, D. W. Bruner, ed., Ithaca, N.Y., 1954) and to improve energy status (see, for example, J. M. DeFrain, et al., “Feeding Glycerol to Transition Dairy Cows: Effects on Blood Metabolites and Lactation Performance,” J. Dairy Sci. 87:4195-4206, 2004 and L. J. Fisher et al., “Preliminary Evaluation of the Addition of Glucogenic Materials to the Rations of Lactating Cows,” Can. J. Anim. Sci., 51:721-727, 1971).
Sugar alcohols and glycerol may provide some energy to a ruminant or mono-gastric animal. Unabsorbed polyalcohols may also create an osmotic effect increasing rate of fecal movement and reducing constipation. As used herein, the term “sugar alcohol” includes carbohydrate residues in open chain form in which the carbonyl functional group of the carbohydrate has been reduced to a hydroxyl group. As used herein, the term “glycerol” includes ethylene glycol, propylene glycol, and glycerol. However, the amount of compound escaping rumen fermentation or being digested may be variable and may require increased amounts of the sugar alcohol or glycerol in order to pass to the intestinal tract. In addition, the hydroscopic nature of these materials may present manufacturing challenges in some feed applications.
Thus, there remains a demand for feed ingredient compounds that exhibit the ability to supply carbohydrate and glucose precursors in the intestinal tract of the animals. Further, there remains a demand for feed ingredient compounds that are resistant to fermentation in the rumen of ruminants and exhibit the ability to pass into the latter portions (i.e., post-rumen portions) of the ruminant digestive system where they can act as carbohydrate and glucose precursors, osmotic agents, and laxatives. The present disclosure addresses these problems and others and provides further advantages that one of ordinary skill in the art will readily discern from the detailed description that follows.